Many automatic vehicle washers are currently in use. Typically, automatic vehicle washers have a number of stations at which a vehicle moving through the washer is sprayed with cleaning liquid, scrubbed and brushed, and dried.
Generally, the cleaning liquid sprayers are in the form of a stationary array of nozzles through which cleaning liquid is ejected under pressure as the vehicle passes the nozzles. Very often, such units are not adequately effective in cleaning vehicles For example, the front and rear of the vehicle normally accumulates more road dirt and grime than the hood or top. A single pass of the vehicle through a stationary sprayer unit may provide insufficient exposure to the high pressure spray to clean the front or rear of the vehicle.
Also, stationary liquid sprayers are designed for the largest dimensions of the largest vehicle which the washer is expected to clean. Consequently, certain surfaces of the largest expected vehicle and certain surfaces of smaller vehicles receive the liquid spray at a reduced pressure, whereby a portion of the cleaning effect due to the liquid hitting against the vehicle is lost.
These and other problems associated with stationary liquid sprayers have prompted development of movable nozzle arrays which apply the cleaning liquid in closer proximity with the vehicle or expose the vehicle to more of a spray than is possible with a single pass of the vehicle through a stationary nozzle array. For example, certain vehicle washers have liquid sprayers which swing back-and-forth along the path of movement of the vehicles. Others have sprayers which spring up from the conveyor as the vehicle approaches to clean the front of the vehicle and as the vehicle passes to clean the rear of the vehicle.
For the most part, moving liquid sprayers developed to date have not satisfied concurrently the requirements of properly cleaning the vehicles and efficient operation. While the spraying time has been increased to expose the vehicle to more liquid spray, the sprayers currently in use are not arranged to maximize the cleaning effect of the sprayers nor are they arranged to spray those portions of the vehicle which most require cleaning with adequate spray.
U.S. Pat. No. 4,562,848 issued to Messing et al discloses a car cleaning system in which nozzles are moved radially along a bar which is swung to allow the nozzles to pass over the car. However, Messing et al does not disclose a practical way to allow the nozzles to dwell sufficiently upon the areas of the car which accumulate more road dirt and grime.